<form [formGroup]='myForm' >
    <div class="form-group">
      <label for="name">name</label>
      <input type="text"  id="name" name="name" formControlName="name">
    </div>
    <div class="form-group">
      <label for="password">password</label>
      <input type="text"  id="password" name="password" formControlName="password">
    </div>
    <div class="form-group">
      <label for="newpassword">new password</label>
      <input type="text"  id="newpassword" name="newpassword" formControlName="newpassword">
    </div>
</form>
<div class="d-flex justify-content-center">
  <button type="button"  (click)="look()">查</button>
  <button type="button"  (click)="add()">增</button>
  <button type="button"  (click)="updata()">改</button>
  <button type="button" (click)="delete()">删</button>
</div>
<table class="table">
    <thead>
      <tr>
        <th scope="col">#</th>
        <th scope="col">Sno     </th>
        <th scope="col">name      </th>
        <th scope="col">password   </th>
      </tr>
    </thead>
    <tbody>
      <tr *ngFor='let user of users$; let i = index'>
        <th scope="row">{{i}}</th>
        <td>{{user.id}}</td>
        <td>{{user.name}}</td>
        <td>{{user.password}}</td>
      </tr>
    </tbody>
</table>